The murderers of the Holocaust were not simply ideological fanatics or uneducated thugs. Dr Johann Paul Kremerwas a professor of anatomy who served with the SS at Auschwitz-Birkenau in late 1942. He performed selections of prisoners, choosing who was fit to work and who would be sent straight to their death. Alongside these Sonderaktions, he extracted organs from victims. He recorded these activities in his diary alongside descriptions of everyday events. The diary offers a powerful insight into the psychological mentality of a perpetrator.

6 September 1942Today Sunday, excellent luncheon: tomato soup, half a chicken with potatoes and red cabbage (20 g fat), dessert and wonderful vanilla ice-cream. After the meal the new medical officer, Obersturmführer Wirths, who comes originally from Waldbröl was welcomed. Sturmbannführer Fietsch in Prague was his former regimental doctor.

I have now been in the camp for a week but I still have not completely got rid of the fleas in my hotel room despite all the counter-measures with Flit (Cuprex) etc…In the evening at 8.00 went to another Sonderaktion outside.

9 September 1942This morning received excellent news from my lawyer in Münster, Prof. Dr Hallermann: from the first of this month I am divorced from my wife. I can now see life in all its colours again. A black curtain has risen from my life! Was later present at corporal punishment of eight prisoners and an execution with a small-bore rifle.

Kremer was captured after the war, as shown in the photograph. He was sentenced to death for his crimes in Auschwitz by a Polish court in 1947 but this was later commuted to life imprisonment. He was released in 1958 and died peacefully of natural causes in 1965.